Identification

Description

Valves are distinctly clavate in shape. The headpole is either subrostrate, or broadly rounded. The footpole is broadly rounded. The axial area is relatively narrow, straight, widening only slightly to form a narrowly elliptical central area. A single stigma is present in the central area. The raphe is lateral and weakly undulate. The external distal raphe ends are deflected at the poles onto the mantle, in the direction opposite the side bearing the stigma. External proximal raphe ends are dilated. Striae are distinctly biseriate, radiate throughout the length of the valve. Longitudinal lines are evident on either side of the axial area, positioned 1/5-1/4 of the way between the valve margin and the axial area. Two conspicuous spines are present at the headpole. The footpole bears distinct apical pore fields. Septa and pseudosepta are present at the apices.

Distribution: Gomphoneis mammilla has been verified from the west coast and at higher elevations in the Rocky Mountains of the U.S.

Autecology

Original Description

  • Basionym
    Gomphonema mammilla
  • Author
    Ehrenb. 1854

Cite This Page

Kociolek, P. (2011). Gomphoneis mammilla. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/gomphoneis_mammilla

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gomphoneis mammilla from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.